These are the fat pets who are so obese they have been enrolled in an animal slimming competition to shed the pounds.

The 13 whoppers – who together weigh a huge 296kg (46st 8lb) - have been picked to take part in the dieting bonanza .

Fat finalists include Curvy Cilla, who weighs in at nearly 8st 8lbs (54.4kg), and her pal Shyla who tips the scales at a hefty 7st 13lbs (50.2kg).

Their owner used to give the heavyweight hounds treats including crumpets, pasta, and biscuits - together the portly pooches need to lose nearly 4st (24.6kg).

Cilla the dog is a whopper (Image: PDSA)

The heaviest cat in the competition is Lucy who ate and slept her way to a colossal 1st 5lbs (8.8kg) – around 120% overweight.

Her owner mistakenly thought she was pregnant and fed the fat feline double portions.

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Tipping the scales at nearly a stone, is seven-year-old chubby Chihuahua Tyty whose weight-gain has been caused by his thieving ways.

Tyty the Chihuahua's weight belies her small breed (Image: PDSA)

He may be smaller than most dogs but is a cheeky chap when it comes to food.

The hound takes the lion’s share from his canine housemates even stealing potentially deadly treats like chocolate bars from his owner.

Sizeable kitty Puff, from Sheffield now tips the scales at 1st 3lb (7.5kg), making her around 50% overweight.

Puff the cat is one fat feline (Image: PDSA)

With the help of her owner she has already lost 5lb since being re-homed last year.

Four-year-old English Bulldog Ethel, from Manchester, has a weight problem due to an injury.

Her family admit to spoiling her, but say their dog has ballooned in size after she suffered a tear to her cruciate ligament last year which prevented her exercising.

She currently weighs in at 4st 13lb (30.3kg), making the her a chubby 50% overweight.

Pebbles the rotund rabbit once weighted in at a colossal 10Ib (4.5kg), making him more than 50% over his ideal weight.

Jack the cat is somewhat overweight (Image: PDSA)

The three-year-old lardy leporine from Blackpool piled on the pounds through a combination of poor quality rabbit food and his aversion to rain, which prevented him exercising.

Sadly, overweight pets are a big problem.

The PDSA, who organised the slimming competition, estimates around one-third of UK dogs and a quarter of cats are now overweight or obese.

Animals can become obese when they are fed scraps or leftovers as their main meals or too many fatty, sugary and, in some cases dangerous, foods including cake, chocolate biscuits, crisps, chips, and even takeaways.

Nicola Martin, PDSA Head of Pet Health and Welfare, said: “Pet obesity is a serious issue affecting millions of UK pets. Like humans, pets carrying excess weight risk developing serious health conditions such as diabetes, arthritis and heart disease. It can even shorten their lives.

Oscar the dog is determined to lose weight (Image: PDSA)

Oscar's owner has enrolled him in the competition (Image: PDSA)

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“Too many pets are being fed unsuitable diets and not receiving enough exercise. So it’s vital we educate owners on how to keep their pets fit and healthy before the problem gets even worse. If owners are unsure what to feed their pets, or are concerned about their weight, they should always seek advice from their vet.

Nicola added: “With the help of PDSA Pet Fit Club, these pets and their owners will be making positive changes to their lifestyles to help them slim down to a healthy weight. PDSA will support them every step of the way over the next six months to ensure they succeed.”

PDSA Pet Fit Club was launched in 2005 and has helped 74 dogs, 32 cats and 6 rabbits lose a total 63 stone 11lb.

For more information about this year’s pet finalists and to follow their progress visit www.petfitclub.org.uk